A prefilled medical injection device with production specific elements is provided as a single use disposable injection device that is optimally suited for mass production through the Blow Fill Seal manufacturing process. The device utilizes a valve and a needle assembly fused to an insert. The valve and the needle assembly are positioned within the insert forming a conduit. The needle assembly is covered with a needle cap that is detachably coupled to protecting the needle assembly from contamination and a user from accidental needle stick. The insert is engaged to the bellows during the BFS manufacturing process and hermetically sealed by a parison layer that covers exterior portion of the insert and the needle cap. The parison layer is formed and trimmed creating exterior features that facilitate the use of the prefilled medical injection.